In a conventional IC tag, a coil is wound around the IC tag usually parallel to a surface of the IC tag. When such tag is attached to or placed on a metal face, magnetic components generated by the coil are compensated by magnetic components generated by an induced electric current generated by an image effect of the metal face.
In order to improve such compensation, a magnetic sheet is inserted between the coil and the metal face, so that induced magnetic components are deviated. On the contrary, as disclosed in reference 1, induced magnetic components can be interacted with the coil so as to double a voltage generated in the coil by utilizing the image effect of the metal face positively.    Cited Reference 1: Japanese utility model registered No. 3121577